GMO (Genetically Modified) Foods? What's the deal?

What does the collective think about this? Good, bad, or ugly? I’ve really never understood why everyone’s panties are in a wad over this. Is there some genuine thing to be concerned about? Or is just fear mongering?
I find it somewhat ironic that opponents call it Frankenfoods, when the monster was in fact the protagonist, and the ignorant villagers who wanted to snuff out its life the antagonists.